<p>Extrusion-based 3D printing technology has emerged as an effective strategy for bone tissue regeneration owing to its high precision and well-controlled pore structures. Polycaprolactone (PCL), a biodegradable polymer, is widely used to fabricate 3D printed scaffolds; however, its inherent hydrophobicity limits cell adhesion and proliferation. In this study, we developed 3D-printed PCL scaffolds with enhanced surface functionality by introducing a polydopamine (PDA) coating to improve hydrophilicity and introducing polydeoxyribonucleotide (PDRN), a biologically active DNA polymer known to promote tissue regeneration. The surface morphology and physicochemical properties of the prepared scaffolds (PCL, PCL/PDA, and PCL/PDA/PDRN) were systemically evaluated and compared. In vitro experiments using MG63 osteoblast-like cells revealed that the PCL/PDA/PDRN scaffolds exhibited significantly improved cell adhesion, proliferation, and osteogenic differentiation compared with unmodified PCL scaffolds. These findings demonstrate that PDA coating provides an effective platform for bioactive molecule immobilization, while PDRN enhances osteogenic potential. Therefore, 3D-printed PCL scaffolds functionalized with PDA and PDRN show great promise for widespread applications in bone tissue engineering.</p> Graphical abstract <p>Schematic illustration of PCL scaffold functionalization by PDA coating and PDRN immobilization. This modification enhanced hydrophilicity, protein adsorption, cell proliferation, and osteogenic potential, supporting bone tissue regeneration.</p>